Petroleum hydrocarbon compositions

ABSTRACT

An additive having detergency and lubricity properties for incorporation in petroleum hydrocarbon and petroleum hydrocarbon compositions containing said additive. The additive is the condensation product of a polyetherpolyester polyol containing from 2 to about 12 hydroxyl groups and a monocarboxylic acid wherein about 85-100 percent of the hydroxyl groups of the polyol are esterified by condensation with the monocarboxylic acid. The additive is generally incorporated in hydrocarbon fuels and hydrocarbon lubricating oils, but its greatest utility is in hydrocarbon lubricating oils. The preferred lubricating oil composition is a two-cycle engine oil comprising a major proportion of a hydrocarbon lubricating oil and a minor proportion of the additive of this invention.

United States Patent Kerschner et a1.

[5 1 PETROLEUM HYDROCARBON COMPOSITIONS Assignee:

Filed:

Inventors: Paul M. Kerschner, Trenton;

Alphonso W. Marcellis, Boonton, both of NJ.

Cities Service Oil Company,

Cranbury, NJ.

Feb. 1, 1973 Appl. No.: 328,572

Related U.S. Application Data Division of Ser. No. 139,142, April 30, 1971.

U.S. Cl 252/56 R, 44/58, 44/66,

Int. Cl Cl0m 1/26 Field of Search 44/58, 70, 66; 252/56 R;

260/784 EP, 78.4 E, 75 EP, 22 R, 76

References Cited UNITED STATES PATENTS 1 5] Mar. 11, 1975 3,427,267 2/1969 Stiegern, ..260/22R 3,455,886 7/1969 Versnel 260/784 EP Primary Examiner-Daniel E. Wyman Assistant Examiner-Mrs. Y. H. Smith Attorney, Agent, or Firm-Edwin T. Yates; John W. Carpenter 1 1 ABSTRACT An additive having detergency and lubricity properties for incorporation in petroleum hydrocarbon and petroleum hydrocarbon compositions containing said additive. The additive is the condensation product of a polyetherpolyester polyol containing from 2 to about 12 hydroxyl groups and a monocarboxylic acid wherein about 85-100 percent of the hydroxyl groups of the polyol are esterified by condensation with the monocarboxylic acid. The additive is generally incorporated in hydrocarbon fuels and hydrocarbon lubricating oils, but its greatest utility is in hydrocarbon lubricating oils. The preferred lubricating oil composb tion is a two-cycle engine oil comprising a major proportion of a hydrocarbon lubricating oil and a minor proportion of the additive of this invention.

4 Claims, No Drawings PETROLEUM HYDROCARBON COMPOSITIONS This is a division, of application Ser. No. 139,142, filed Apr. 30, 1971.

BACKGROUND OF THE INVENTION Petroleum hydrocarbon products often require the addition thereto of various additives to improve various properties. There is often a need, for example, to im part carburetor detergency and upper cylinder lubricating properties to a gasoline composition. Also, there is often a need to impart detergency properties and to enhance the lubricity of a lubricating oil composition. The need for detergency arises from the necessity to keep engine parts free from varnish and sludge build-up as well as the need to keep combustion products and sludge in suspension in the oil.

The foregoing is especially true in the case of twocycle engine operation where the lubricating oil is mixed with the fuel. The main requirement is to keep the pistons and rings free from deposits, the principal cause of which is incomplete combustion of the fuel/oil mixture to form deposit precursors. The deposit precursors then polymerize to resins which form varnish and sludge.

Another type of deposit build-up in two-cycle engines is the accumulation of carbon deposits in the exhaust ports or the muffler system. Such deposit buildup results in back pressure which causes power loss, particularly with smaller engines. Therefore, the residue from the combustion of the oil, which is burned with the fuel in the combustion chamber, should be in the form of a friable ash which does not build up in critical areas.

Still another type of deposit build-up is the formation of a whisker of lead salts across the electrode gap of the spark plug. This necessitates frequent plug removal and cleaning.

The mechanism for deposit control due to the presence of a detergent, or dispersant, in the lubricating oil is postulated to be similar in two-cycle and four-cycle engines. The detergent is adsorbed on the carbonyl and carboxyl groups of the droplets of deposit precursors and resins to form a protective film which prevents these droplets from agglomerating into varnish and sludge. These detergents also keep the deposit precursors and resins suspended in the air/fuel mixture within the combustion chamber for more complete burning or to exit with the gases at the exhaust ports. 1n addition, the detergent present in the crankcase oil of four-cycle engines keeps combustion products and sludge in suspension in the oil to thereby prevent sludge build-up in the crankcase.

It is proposed that the ability of detergent additives to surround deposit precursors and resin droplets is a function of the detergents ability to plate out on the surface of the metal where it acts as a lubricant in its own right, thus enhancing the lubricity of the oil composition. lt is well known that the frictional properties of oils are related to the rate of chemical and/or physical adsorption, the number of layers adsorbed, and the strength of the adsorbed film. Thus there is an apparent relationship between frictional properties of engine oils and engine cleanliness, i.e., the higher the degree oflubricity of the oil, the cleaner the engine. Therefore, the lubricity due to an additive of this invention is a function of its dispersant power. Accordingly, by measuring the lubricity of an oil composition containing a detergent additive, a measure of the additives dispersing power is obtained.

It is a desirable feature oflubricating oil additives that they be thermally stable in view of the elevated temperatures to which they are subjected. This is par ticularly true in the case of two-cycle engine oils where the oil is mixed with and burned with the fuel.

SUMMARY It is an object of this invention to provide an additive for hydrocarbon petroleum products having detergency properties.

It is another object of this invention to provide an ashless additive for petroleum hydrocarbon products having, in addition to detergency properties, thermal stability and lubricity characteristics as well as rust inhibitory. properties.

It is yet another object of this invention to provide hydrocarbon petroleum compositions having improved detergency and'lubricity characteristics.

Still another object of this invention is to provide a lubricating oil composition having, in addition to improved detergency properties, enhanced lubricity and thermal stability as well as rust inhibitory characteristics.

Other objects and advantages of this invention will be apparent to those skilled in the art from this disclosure.

The foregoing objects are achieved in accordance with this invention. In general, this invention consists of an additive for petroleum hydrocarbon products comprising the condensation product of a polyether polyester polyol having 2 to about 12 hydroxyl groups and a monocarboxylic acid wherein at least about percent of the hydroxyl groups of said polyol are converted to ester groups by condensation with said monocarboxylic acid; and a petroleum hydrocarbon composition comprising a major proportion of a petroleum hydrocarbon and a minor proportion of the additive of this invention.

Thus by practicing the instant invention, an ashless detergency additive for petroleum hydrocarbon products is obtained. The additive has, in addition to detergency properties, thermal stability and lubricity characteristics as well as rust inhibitory properties. Petroleum hydrocarbon compositions, particularly hydrocarbon lubricating oil compositions, containing the additive of this invention exhibit thermal stability and rust inhibitory properties as well as increased lubricity and detergency characteristics. In addition, engines lubricated by hydrocarbon lubricating oil compositions of this invention are characterized by enhanced cleanliness.

DESCRIPTION OF THE PREFERRED EMBODIMENTS This invention is concerned with ashless detergency additives for petroleum hydrocarbon products and petroleum hydrocarbon product compositions containing said additives. The additives of this invention impart to petroleum hydrocarbon products superior detergency properties as well as enhanced lubricity. Petroleum hydrocarbon compositions of this invention are also characterized by improved thermal stability as well as enhanced rust inhibitory properties. While the additives of this invention may be used in petroleum hydrocarbon products generally, they are particularly useful in gasoline and hydrocarbon lubricating oils, especially two-cycle engine oils. Engines lubricated with the hydrocarbon lubricating oil compositions of this invention exhibit enhanced cleanliness.

The detergency additive of this invention broadly comprises the condensation product of a polyetherpolyester polyol having 2 to about 12 hydroxyl groups and a monocarboxylic acid wherein at least about 85 percent of the hydroxyl group of said polyol are converted to ester groups by condensation with said monocarboxylic acid.

The polyether-polyester polyol is a hydroxylterminated polymer which comprises chains containing both ether andester linkages. Such polyols are described in U.S. Pat. No. 3,455,886. The polyols are characterized in that the sequence of ester and ether units in the polymer chain is ordered. For example, a typical chain of the polyether-polyester polyol may be represented by:

A-C-R-C-O-R OR OR OH i Where R represents the residue of an anhydride of a polybasic organic acid, R represents the residue of a cyclic ether, and A represents a structure grouping contained in a polymerization starter molecule.

While the polyether-polyester polyols are described in detail in US. Pat. No. 3,455,886, broadly the polyols are characterized by having at least 2, and preferably 2 to about 12, hydroxyl groups,, a relatively low viscosity at room temperature, and a narrow molecular weight distribution. In general, they have an equivalent weight of from about 80 to 300, and a hydroxyl number of from 187 to 700.

These hydroxyl-terminated polymers containing both ether and ester linkages are produced by reacting an anhydride of an organic polycarboxylic acid with a suitable polymerization starter compound containing at least two groups selected from the group consisting of alcoholic hydroxyls, primary amines, secondary amines, and combinations thereof, to form a partial ester or partial amide, substantially free of unreacted anhydride. This intermediate reaction product is then reacted with an excess, based on the amount of anhydride reacted, of a cyclic ether containing at least one heterocyclic ring comprising 1 ethereal oxygen and at least 2 carbons to form the polyol.

More particularly, the polymerization starter and anhydride reactants are reacted in amounts such that the ratio of equivalents of anhydride to equivalents of starter is from about 0.1 to about 2.0. The conditions of this first stage reaction are such that all or substantially all of the anhydride reacts with the hydroxyl or amine groups of the starter leading to the formation of a partial ester or partial amide and generating carboxyl groups. This intermediate reaction product is then caused to react with a cyclic ether in an amount of from about L5 to about 14 equivalents per equivalent of anhydride employed in the first stage reaction to form the polyether-polyester polyol.

The polyether-polyester polyol is described in detail in U.S. Pat. No. 3,455,886. In the patent, the various components used to prepare the polyol, i.e., the starter compound, the polycarboxylic acid anhydride, and the cyclic ether, are described and numerous examples given. Also described are the ratios of starter compound, acid anhydride, and cyclic ether as well as reaction conditions for formation of the polyol. The properties of the polyol are also given. It has been found for the purposes of the instant invention that the preferred polyether-polyester polyol is prepared using glycerol as the starter compound, phthalic anhydride as the polycarboxylic acid anhydride, and propylene oxide as the cyclic ether. The resultant polyol contains 3 hydroxyl groups and has a preferred equivalent weight of about 130.

The monocarboxylic acid broadly contains about 8 to 30 carbons and preferably about 12 to 24 carbons. The monocarboxylic acid may be an aliphatic acid, preferably a branched chain aliphatic acid; an'aromatic acid containing a branched aliphatic chain having at least I 2 carbons on the aromatic ring; or a naphthenic acid con- .taining a branched aliphatic chain having at least 12 carbons on the naphthenic ring. The preferred class of monocarboxylic acids are the branched chain aliphatic acid containing about 8 to 30, and preferably about 12 to 24, carbons. Examples of suitable monocarboxylic acids are S-methylheptanoic acid, 2-ethyl-hexanoic acid, 9-ethyldodecanoic acid, phenylstearic acid, 18- butyleicosoic acid, 8-ethyldecanoic acid, pisostearylbenzoic acid, 4-isododecyl-lcyclohexanoic acid, 4-(l7-ethyloctadecyl)-Lnaphthoic acid, 1- isododecyl5-carboxycyclooctane, tallow fatty acid such as Emery 500 Fatty Acid, and mixtures thereof. The preferred monocarboxylic acid is isosteraric acid.

The ratio of monocarboxylic acid to the polyetherpolyester polyol is such as to convert about to percent of the hydroxyl groups of the polyol to ester groups by condensation with the monocarboxylic acid. In the case where the additive is the condensation product of isostearic acid and a polyether-polyester polyol prepared from glycerol, phthalic anhydride, and propylene oxide, it is preferred that about 100 percent of the hydroxyl groups of the polyol be converted to ester groups by condensation with the isostearic acid.

the petroleum hydrocarbon compositions of our invention broadly comprise a major proportion of a petroleum hydrocarbon product and a minor proportion of the inventive additive. Generally, the petroleum hydrocarbon compositions contain about 1 to 20 percent by volume, based on the hydrocarbon composition, of the additive of this invention. It is preferred that the petroleum hydrocarbon composition contain about 3 to 15 percent by volume, based on the petroleum hydrocarbon composition, of the additive.

The additives of the instant invention are useful in petroleum hydrocarbon products generally. However, it is contemplated that the additives will have their greatest utility in gasoline and in hydrocarbon engine oils, particularly in two-cycle engine oils. The detergency additives of this invention will find utility in gasoline as carburetor detergency additives and as upper cylinder lubricants. It is anticipated that the detergency additives of this invention will be most useful in hydrocarbon engine oils, especially two-cycle engine oils, to produce hydrocarbon lubricating oil compositions having enhanced detergency and lubricity characteristics as well as thermal stability and rust inhibitory properties.

Our invention will be further illustrated by the following specific examples.

EXAMPLE I To a 500 ml. round bottom flask fitted with magnetic stirrer, thermometer, Dean-Stark trap, condenser, and nitrogen-inlet tube are added 77.2g. (0.6 eq.) of a polyether-polyester polyol having an equivalent weight of 130 and which is prepared using glycerol as the the system. At the end of this time ml. of water of k condensation, 92.6 percent of the theoretical amount for ester formation, are collected in the Dean-Stark trap. The xylene is removed by distillation under reduced pressure at a temperature of 100-l60C to leave a residue of 252g. of a light yellow, free flowing liquid. Infrared spectroscopy shows the product to be essentially free of absorptions due to the presence of hydroxyl and carboxyl functionalities while absorption at 1,740 cm. shows the presence of ester carbonyl groups. The product has an acid number of l5.6 mg. KOH/g. indicating the presence of some unreacted acid. The solubility of the product in base hydrocarbon oil is greater than 10 volume percent.

As mentioned above, the effectiveness of the additives of this invention as dispersants in lubricating oil compositions is indicated by and is a function of the lubricity imparted to the oil composition by said additives. From friction data, the Lubricity Index (LI at six different temperatures is determined. The Normal Lubricity index (NLI) is the average of the Lubricity lndexes at the six temperatures. The Lubricity Index is determined from the expression:

LI a/A b/B b'lB d/D DId wherein the lower case letters are for frictional values of a standard oil composition and the upper case letters are the corresponding frictional values for an oil composition containing the experimental additive of this invention.

a static coefficient of friction b coefficient of friction at 2 fpm b coefficient of friction at 50 fpm d coefficient of slip-stick or (static coefficient of friction/coefficient of friction at 2 fpm) d ratio of coefficient of friction at 10 fpm to coefficient of friction at 100 fpm LI Lubricity Index at TF The lubricity Index is determined at 100F, 150F, 200F, 250F, 300F, and 350F. The Normal Lubricity Index (NLI), an average of these 6 Lubricity lndexes, is represented by the expression:

NLI (Ll 1.1 L1 L1 Li LI )/6 From the foregoing it can be seen that if an oil composition containing an additive of this invention is equal in lubricity to the standard oil composition at a given temperature T, it will have a value for LI of 100. A value for LI less than 100 indicates poorer lubricity than the standard and a value for LI greater than 100 indicates better lubricity than the standard at temperature T. The same holds true for Normal Lubricity Index (NLI) which is an average of the Lubricity Indexes at the 6 different temperatures. Thus if an oil composition I containing an additive of this invention has a NLI value greater than 100, it will have greater lubricity than the standard oil composition and hence it will have better dispersant power.

The friction data are obtained by using the friction apparatus and procedure described by Hain in a paper entitled Performance of Oil Additives. The paper was presented at Session 5C of a convention of the American Society of Lubrication Engineers at Chicago, II]. on May 28, 1964.

The friction apparatus is essentially a modified drill press containing a temperature recorder, a variable speed motor, and a single channel strain gauge to measure coefficient of friction. The friction couple used in these experiments is blotter paper vs. polished, cold rolled steel. The blotter paper is chosen because of its consistent porosity and surface roughness. The consistent porosity insures uniform results from day to day.

A two-cycle engine oil composition is prepared containing 10 volume percent of the inventive additive for which the preparation is described above. The standard oil composition, which by definition has a NLl of 100, is a two-cycle engine oil composition containing 10 volume percent of a commercially available additive. The two-cycle engine oil composition containing the additive of the invention is found to have a NLI of 121 while a base two-cycle engine oil containing no additive has a NLI of 9i.

Since, as pointed out above, an increase in the lubricity of a two-cycle engine oil results in improved engine cleanliness, a two-cycle engine operating on a fuel/oil mixture in which the oil contains the lubricityimproving additive of this invention will operate cleaner with less deposit build-up than it will on a similar fuel/oil mixture in which the oil contains either no additive or contains the commercially available additive.

EXAMPLE II A number of lubricating oil compositions are prepared containing various concentrations of the inventive additive of Example I. The interfacial tension (IFT) between each lubricating oil composition and water is compared to that between a base lubricating oil containing no additive and water. The percent reduction if IF T is determined from the expression:

(IFT IFT,,,,,,,,, )/(IFT,,,,,,,) Reduction in IF T Table I shows the percent reduction in [FT for each lubricating oil composition containing the additive of Example I. All concentrations are volume percent of additive based on the total lubricating oil composition.

TABLE I Additive Concentration. vol.% %lFT Reduction EXAMPLE III additive is soluble in hydrocarbon oil to the extent of greater than about 10 volume percent. A lubricating oil The thermal and oxidative stabilities of a lubricating 7 oil composition containing an additive of this invention are determined. A 15 ml. sample of a lubricating oil composition containing 10 volume percent of the additive of Example 'I is heated in a test tube at 375F for 10 days. The hot solution is then decanted. The test tube is allowed to drain and is examined for sludge deposits. A lubricating oil composition containing 10 volume percent of a commercially available additive is similarly tested as a comparison. No oil-insoluble sludge is found in either oil composition at the conclusion of the test. Base oil alone similarly tested gave sludge formation.

EXAMPLE IV A lubricating oil composition containing 'volume percent of the inventive additive of Example I and a base hydrocarbon lubricating oil containing no additive are subjected to the Shell Four Ball Wear test. The test involves placing three stationary steel balls in triangular configuration in a cup containing the oil composition to be tested while a fourth ball which is rotatable and capable of having a load applied thereto is brought into contact with the three stationary balls in such a way as to form a tetrahedron. The conditions of the test are to rotate the fourth ball at 1,800 rpm. at a temperature of I60F for 1 hour. The test is run under a load of 7.5 kg. At the end of the test, the wear, i.e., the average of the scar diameters of the three stationary balls, is determined. The greater the wear, the poorer the lubricity of the oil composition. The results of the test are shown in Table II.

TABLE II Additive Concentration in the Lubricating Oil Compo- Additive sition, vol.% Wear, mm.

0.47 Additive of Example l 10 0.29

From Table II it is seen that the oil composition containing the inventive additive of Example I permits less wear than does the base hydrocarbon oil containing no additive.

EXAMPLE V EXAMPLE VI An additive according to this invention is prepared by following the procedure described in Example I wherein 0.3 eq. of phenylstearic acid and 0.3 eq. of the polyether-polyester polyol described in Example I are condensed. Infrared analysis indicates the additive product to be 100 percent converted to the ester. The

composition containing 10 volume percent of the inventive additive has a NLI of I 10 relative to a standard oil composition containing 10 volume percent of a commercially available lubricity additive which by definition has a NLI of 100. In addition, the oil composition containing the inventive additive exhibits thermal stability as good as that of the oil composition containing the commercial additive.

The additive of this invention may be prepared by condensing a monocarboxylic acid containing about 8 to 30 carbons with a polyether-polyester polyol of the type disclosed in U.S. Pat. No. 3,455,886. While a pre ferred polyether-polyester polyol prepared from glycerol, phthalic anhydride, and propylene oxide has been exemplified herein, it will be understood that polyeth er-polyester polyols within the scope of U.S. Pat. No. 3,455,886 may in general be condensed with a suitable monocarboxylic acid to yield our detergency additive. The additive may be prepared by condensing the polyether-polyester polyol with, for example, 5-

methylheptanoic acid, 2-ethylhexanoic acid, 9- ethyldodecanoic acid, phenylstearic acid, 18- butyleicosoic acid, 8-ethyldecanoic acid, p-

isostearylbenzoic acid, 4-isododecyl-l-cyclohexanoic acid, 4-(17-ethyloctadecyl)-l-naphthoic acid, 1- isododecyl-S-carboxycyclooctane, isostearic acid, and mixtures thereof. The ratio of monocarboxylic acid to the polyether-polyester polyol is such as to convert about 85 to 100 percent, and preferably 100 percent, of the hydroxyl groups of the polyol to ester groups by condensation with the monocarboxylic acid.

The petroleum hydrocarbon compositions of our invention broadly comprise a major proportion of a petroleum hydrocarbon product and a minor proportion of the inventive additive. Generally, the petroleum hydrocarbon compositions contain about 1 to 20 percent by volume, and preferably about 3 to 15 percent by volume, of the additive of this invention. The additives of the instant invention are useful in petroleum hydrocarbon products generally, but it is contemplated that the additives will have their greatest utility in gasoline and in hydrocarbon engine oils, particularly in two-cycle engine oils.

While our invention has been illustrated by various specific examples, it will be understood that the scope of our invention is not restricted thereto.

We claim:

l. A petroleum hydrocarbon composition comprising a petroleum hydrocarbon and from between about 1 to 20 percent by volume of a condensation product of a polyether-polyester polyol having 2 to about 12 hydroxyl groups and a monocarboxylic acid wherein at least about percent of the hydroxyl groups of said polyol are converted to ester groups by condensation of said monocarboxylic acid containing about 1224 carbon atoms 2. A petroleum hydrocarbon composition comprising a petroleum hydrocarbon selected from the group consisting of gasoline and hydrocarbon lubricating oils and about 1 to 20 percent by volume of a condensation product of a polyether-polyester polyol having 2 to about 12 hydroxyl groups and a monocarboxylic acid, said monocarboxylic acid is an isoaliphatic acid containing about 12 to 24 carbons and about 85 to percent of the hydroxyl groups of said polyol are converted to ester groups by condensation with said isoaliphatic acid.

3. A petroleum hydrocarbon composition comprising a petroleum hydrocarbon selected from the group consisting of gasoline and hydrocarbon lubricating oils and about 3 to percent by volume of a condensation product of a polyether-polyester polyol having 2 to about 12 hydroxyl groups and a monocarboxylic acid, said monocarboxylic acid is an isoaliphatic acid con taining about 12 to 24 carbons and about 85 to 100 percent of the hydroxyl groups of said polyol are converted to ester groups by condensation with said isoaliphatic acid, said isoaliphatic acid is isostearic acid.

4. A two-cycle engine oil composition comprising a hydrocarbon lubricating oil in about 3 to 15 percent by volume of a condensation product of a polyetherpolyester polyol having 2 to about 12 hydroxyl groups and a monocarboxylic wherein at least about percent of the hydroxyl groups of said polyol are converted to ester groups by condensation with said monocarboxylic acid, said monocarboxylic acid is an isoaliphatic acid containing about 12 to 24 carbons and about 85 to percent of the hydroxyl groups of said polyol are converted to ester groups by condensation with said isoaliphatic acid, said isoaliphatic acid is isostearic acid. 

1. A petroleum hydrocarbon composition comprising a petroleum hydrocarbon and from between about 1 to 20 percent by volume of a condensation product of a polyether-polyester polyol having 2 to about 12 hydroxyl groups and a monocarboxylic acid wherein at least about 85 percent of the hydroxyl groups of said polyol Are converted to ester groups by condensation of said monocarboxylic acid containing about 12-24 carbon atoms
 1. A PETROLEMUM HYDROCARBON COMPOSITION COMPRISING A PETROLEUM HYDROCARBON AND FROM BETWEEN ABOUT 1 TO 20 PERCENT BY VOLUME OF A CONDENSATION PRODUCT OF A POLYETHERPOLYESTER POLYOL HAVING 2 TO ABOUT 12 HYDROXYL GROUPS AND A MONOCARBOXYLIC ACID WHEREIN AT LEAST ABOUT 12 HYDROXYL GROUPS AND HYDROXYL GROUPS OF SAID POLYOL ARE CONVERTED TO ESTER GROUPS BY CONDENSATION OF SAID MONOCARBOXYLIC ACID CONTAINING ABOUT 12-24 CARBON ATOMS.
 2. A petroleum hydrocarbon composition comprising a petroleum hydrocarbon selected from the group consisting of gasoline and hydrocarbon lubricating oils and about 1 to 20 percent by volume of a condensation product of a polyether-polyester polyol having 2 to about 12 hydroxyl groups and a monocarboxylic acid, said monocarboxylic acid is an isoaliphatic acid containing about 12 to 24 carbons and about 85 to 100 percent of the hydroxyl groups of said polyol are converted to ester groups by condensation with said isoaliphatic acid.
 3. A petroleum hydrocarbon composition comprising a petroleum hydrocarbon selected from the group consisting of gasoline and hydrocarbon lubricating oils and about 3 to 15 percent by volume of a condensation product of a polyether-polyester polyol having 2 to about 12 hydroxyl groups and a monocarboxylic acid, said monocarboxylic acid is an isoaliphatic acid containing about 12 to 24 carbons and about 85 to 100 percent of the hydroxyl groups of said polyol are converted to ester groups by condensation with said isoaliphatic acid, said isoaliphatic acid is isostearic acid. 